A hallmark of Type 2 diabetes is impaired insulin secretion from beta cells of the islets of Langerhans. Greater understanding of islets and insulin secretion is of fundamental importance in determining the root causes of diabetes and developing potential treatments. Studies of islets are critically dependent upon instrumentation that can detect their biochemical and physiological dynamics. Type 1 diabetes is characterized by autoimmune attack on beta cells and subsequent loss of insulin secretion. A promising treatment for type 1 diabetes is transplant of islets; however, this treatment is presently limited by inability to adequately assess islets used in transplant. Therefore, improved tools for studying insulin secretion are crucial for advancing treatments of diabetes. The overall objective of this work is to develop advanced instrumentation suitable for measuring chemical events related to peptide secretion from islets of Langerhans. Our first two aims are to develop microfluidic tools that will allow single islets to be cultured while simultaneously monitoring hormone and metabolite secretion and metabolism. To allow cell-cell interactions to be studied, the microfluidic chip will incorporate a microcirculatory system that allows two different cell types to be cultured and interact during the measurements. Our third aim is to develop high-throughput metabolomic methods for measurement of polar and lipidic metabolites present in insulin-secreting cells. The method will be based on capillary liquid chromatography and capillary electrophoresis with mass spectrometry detection. Throughput of this method will be enhanced through novel fluidic methods and improved data analysis. Our final aim is to use these methods in studies that will: 1) determine metabolites involved in fuel-stimulated insulin secretion; 2) how islet cells are influenced by fat and liver cells; 3) the role of leptin and PPARg receptors in regulating lipid metabolism in islets; and 4) mechanisms of islet oscillations. The methods will also be used in pilot studies to determine if they may be useful assessing islets prior to transplant. These methods will offer new opportunities for studying the root causes of diabetes and devising novel treatments. RELEVANCE (See instructions): Diabetes is an enormous public health problem costing over $100 billion in 2002 in the US. This disease is characterized by impaired insulin secretion from cell clusters known as islets of Langerhans. Our research will result in novel instrumentation that will allow studies ofthe chemical changes associated with normal and diseased islet function in unprecedented detail. Assessment of such chemical changes is expected to help identify novel theraneutic targets.